polycvss

Rust library to parse and score CVSS vector strings.

Features:

• CVSS v2, CVSS v3, and CVSS v4 support.
• Version-agnostic parsing and scoring API.
• Memory efficient: Parsed vectors are 8 bytes. Scores and severities are 1 byte.
• No dependencies except the standard library.
• Extensive tests: Tested against thousands of results from the NVD CVSS score calculators.

Here is an example tool which parses the first command-line argument as a CVSS vector string, then prints the score and severity:

use polycvss::{Err, Score, Severity, Vector};

fn main() -> Result<(), Err> {
  let args: Vec<String> = std::env::args().collect(); // get cli args

  if args.len() == 2 {
    let vec: Vector = args[1].parse()?; // parse string
    let score = Score::from(vec); // get score
    let severity = Severity::from(score); // get severity
    println!("{score} {severity}"); // print score and severity
  } else {
    let name = args.first().map_or("app", |s| s); // get app name
    eprintln!("Usage: {name} [VECTOR]"); // print usage
  }

  Ok(())
}

Here is the example tool output for a CVSS v2 vector string, a CVSS v3 vector string, and a CVSS v4 vector string:

# test with cvss v2 vector string
$ cvss-score "AV:A/AC:H/Au:N/C:C/I:C/A:C"
6.8 MEDIUM

# test with cvss v3 vector string
$ cvss-score "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
9.8 CRITICAL

# test with cvss v4 vector string
$ cvss-score "CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:H/SI:H/SA:H"
5.2 MEDIUM

This example tool is included in the Git repository as src/bin/cvss-score.rs.

Build

Run cargo build to create a debug build of the example tool in target/debug:

$ cargo build
...
$ target/debug/cvss-score "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
9.8 CRITICAL

Run cargo build --release to create a release build of the example tool in target/release:

$ cargo build --release
...
$ target/release/cvss-score "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
9.8 CRITICAL

You can also build the example tool in a container using Podman or Docker like this:

$ podman run --rm -t -v "$PWD":/src -w /src docker.io/rust cargo build --release
...
$ target/release/cvss-score "CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:H/SI:H/SA:H"
5.2 MEDIUM

Documentation

Run cargo doc to build the API documentation in target/doc/polycvss:

$ cargo doc
...
$ ls target/doc/polycvss/index.html
target/doc/polycvss/index.html

Run cargo doc --lib build the library documentation and exclude the example tool:

# remove generated docs
# (needed to clean up stale artifacts)
$ cargo clean --doc

# generate library-only docs
$ cargo doc --lib

Tests

Use cargo test to run the test suite:

$ cargo test
...
test result: ok. 369 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.05s
$

Use cargo clippy to run the linter:

$ cargo clippy
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.04s
$

The test suite includes a large number of scored CVSS vector string test cases. The test cases were generated using cvss-calcs.

The generated test cases can be found in src/v3.rs, src/v3.rs, and src/v4.rs.